Hazim-Lab 2

8/9/2019 Hazim-Lab 2

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UNIVERSITI TEKNOLOGI MARA

FAKULTI KEJURUTERAAN KIMIACHEMICAL ENGINEERING LABORATORY

(CHE574)

NAME : MOHD HAZIM BIN ELIAS

STUDENT NO. : 2004624588

EXPERIMENT : DEEP BED FILTER

DATEPERFORMED

: JANUARY 2006

SEMESTER : DECEMBER 2005 APRIL 2006

PROGRAMME /CODE

: Bachelor of Engineering (Hons.) in ChemicalEngineering/ EH220

Remarks:

Checked by: Rechecked by:Cik Siti Ida Farida bte Abd Razak

ABSTRACT / SUMMARY

No. Title Allocated marks % Marks %1 Abstract/Summary 5

2 Introduction 53 Aims/Objectives 54 Theory 55 Procedures 36 Apparatus 57 Results 208 Calculations 109 Discussions 20

10 Conclusions 1011 Recommendations 512 References 513 Appendices 2

TOTAL 100

PK.FKK.PPM.MANUAL MAKMAL CHE574


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This particular experiment is about separating solid particle from suspension

in liquid. The experiments were conduction using the deep bed filtration apparatus.

This equipment allows particles penetrated into the interstices of the filter bed where

then they are trapped following impingement on the surfaces of the material of the

bed.

The very fine particles of solids are removed by mechanical action but the

particles finally adhere as a result of surface electrostatic forces or adsorption. The

objective of this experiment is to determine the pressure drop across the bed, the

nature of flow in filter bed and to determine the performance of the bed.

Three theory is used to calculate the result, Darcy-Weisbach formulation,

friction factor estimation and pressure drop in porous bed. The result from the

experiment is calculated and graph is plotted.

INTRODUCTION


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Filtration is a physical operation that used largely in industry to separate solid

particle from suspensions in liquid. In a filtration system, porous layer is used where

only liquid is allowed to follow through them.

There are many reasons on why filtration systems are used in industries. They

are:

i. To separate solid particles that has commercial value from liquid or gas.

ii. To separate solid waste from valuable liquid, such as solid suspension from

oil.

iii. To separate both solid and liquid when both have commercial value.

iv. To separate both solid and liquid even if both does not have any commercial

value such as if both is harmful material and has to be disposed accordingly.

Deep bed filter allows particles penetrated into the interstices of the filter bed where

then they are trapped following impingement on the surfaces of the material of the

bed. The very fine particles of solids are removed by mechanical action but the

particles finally adhere as a result of surface electrostatic forces or adsorption.

AIMS / OBJECTIVES


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To determine the pressure drop across the bed

To determine the nature of flow in filter bed

To determine the performance of the bed


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THEORY

Darcy Weisbach Formulation

The formula involves the study of straight pipe in which an incompressible

fluid flows in it. Consider the following functional relationship:

P = f (v, , D, , L, )

Where

P Pressure drop between two points

v Velocity of fluid

Density of fluid

D Pipe diameter

Viscosity of fluid

L length of pipe

Roughness of pipe wall

From above, seven magnitudes are expressed as a function of three basic

dimensions i.e L, M and T, which then form 4 dimensional parameters. By repeating

v, , D and with the addition of other magnitudes, the parameters are:

1 = P 2 = v D 3 = 4 = L

v 2 D D

Thus, we can also express the relationship as dimensional function:

P / v 2 = f (vD / , / D, L /D)

Consider P = gh f , where h f is the loss of total load between two sections of the pipe,

then

hf = (L / D) (v 2 / 2g)


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where is the friction factor from Moody diagram

Friction Factor, Estimation.

Nikuradse and Moody determined the friction factor, experimentally where

Nikuradse used pipes with artificial roughness whilst Moody used commercial pipes

with roughness is the characteristic of the pipe. The results obtained by Moody are

shown in Figure 2 .

From the diagram, following are the parameters that can be considered:

a. For Re < 2000, in the fluid flow, friction factor only dependence on Reynolds

number but not wall roughness, where = 64 / Re

b. The transition region of Reynolds number gives the friction factor,

depending simultaneously on the viscous effects and on the roughness of the

pipe and hence = f (Re, / D)

c. For sufficiently high Re number, the viscous effect do not cause effect and the

friction factor, only depend on the roughness of the wall, where = f ( / D)

Pressure Drop in Porous Beds.

The pressure drop caused by the contact between particles and the media

accompanying the flow of fluid can be calculated using the following general

procedure:

a. Reynolds number of the fluid flow in the packed bed, Re based on the

diameter of the particles, d p and the approach velocity of the fluid to the bed,

va is affected by the correction coefficient, F Re (Figure 3 ) where:

Re = (v ad p / ) F Re


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Where F Re = f (, ) porosity / voidage of the bed

sphericity of particles

b. The friction factor, ( Figure 4 ) depends on Reynolds number, Re, so

= f (Re)

c. The pressure drop in the porous drop gives similar expression to the pressure

drop in pipes but however, it is affected by a correction coefficient, F f (Figure

5):

H f = (L / d p) (v a2 / 2g) (F f )

Where F f = f (, )


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PROCEDURES

Preliminary Experiment

Tank D1 and D2 was filled with clean water. Pump switched on. Valve V 2 and

V2, V 5 and V 7 opened, and valve V 4 and V 6 closed. Valve V 3 was adjusted to

establish flow and the water allowed circulating in 2 to 3 minutes. If there was bubble

trapped in the water manometer column, purging method was applied by increasing

water height in the manometer column until the bubbles disappeared. Total height of

bed measured.

Experiment 1: Lost of Load of a Porous Bed

Valve V 3 adjusted, and if necessary, valve V 2 closed to obtain the difference of

pressure of 1000 mm between tube 1 and 30. The readings from tube 1 to tube 30

were noted. The experiment repeated to get the 10 different flows covering the range

of flowmeter. Before stopping the pump, valve V 2 fully opened and valve V 3 fully

closed to avoid entrance of air to the circuit.

Experiment 2: Loss of Load h f in Function of Depth and Time

Solid-suspension liquid was prepared in tank D2 (about 100 g of flour). The

clarity of the liquid was test using turbidimeter. Valve V 1 and V 2 opened, and valve

V3 closed and pump started. Valve V 3 opened until flow rate, Q = 60 L / hr reached.

When the cloudy suspension reached the packed bed, the timing started and the time

registered. Verify that the flow remains constant and if necessary, the flow adjusted

using valve V 3. The reading repeated in every 30 minutes. The samples were collected

at the 1 st, 2 nd, 6 th, 10 th, 15 th, 20 th, 25 th and 30 th tubes. The turbidity of each samples

measured using turbidimeter. The results recorded. Besides that, the reading of the

tubes also recorded. The length of the column from the base to the respective tappings

measured. The pump stopped when the experiment finished.


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APPARATUS

Deep bed filter

Turbidimeter Stopped watch

Beaker for making the solution of flour

Spatula for stirring the solution of flour


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RESULTS

Experiment 1: Lost of Load of a Porous Bed

Flow Rate, Q (L / hr) h 1 h30 hf = h 1 - h 30 10 572 520 52

20 592 504 8830 612 490 12240 642 468 17450 662 438 22460 682 408 27470 708 380 32880 738 346 39290 764 304 460

100 802 268 534

Table 1: Data for experiment lost of load in a porous bed

Flow Rate, Q (L /hr) Q (m 3 / s) v a (m / s) Re' ' H f (m)10 2.778E-06 3.537E-04 17.684 4.0 0.065720 5.556E-06 7.074E-04 35.368 1.7 0.111630 8.333E-06 1.061E-03 53.052 1.2 0.177340 1.111E-05 1.415E-03 70.735 0.8 0.210150 1.389E-05 1.768E-03 88.419 0.7 0.287360 1.667E-05 2.122E-03 106.103 0.6 0.3546

70 1.944E-05 2.476E-03 123.787 0.5 0.402280 2.222E-05 2.829E-03 141.471 0.4 0.420390 2.500E-05 3.183E-03 159.155 0.4 0.5319

100 2.778E-05 3.537E-03 176.838 0.3 0.5582

Table 2: Table of calculation for theoretical head loss


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Graph of Head Loss versus Flowrate

0

0.1

0.2

0.30.4

0.5

0.6

2 . 7

7 8 E

- 0 6

5 . 5

5 6 E

- 0 6

8 . 3

3 3 E

- 0 6

1 . 1

1 1 E

- 0 5

1 . 3

8 9 E

- 0 5

1 . 6

6 7 E

- 0 5

1 . 9

4 4 E

- 0 5

2 . 2

2 2 E

- 0 5

2 . 5

0 0 E

- 0 5

2 . 7

7 8 E

- 0 5

Flowrate

H e a

d L o s s

experimental value

theoretical value

Experiment 2: Loss of Load h f in Function of Depth and Time

number of L (mm) Lapsed time (minutes)

tube 30 60 90

hf ' turbidity h f ' turbidity h f ' turbidity1 90 670 42.8 690 50.5 694 38.12 120 656 45.6 680 47.1 682 37.36 220 636 48.1 648 40.7 650 32.7

10 320 608 47.6 620 34.8 622 30.115 440 570 45.1 580 34.6 574 33.820 570 542 39.6 540 33.1 538 29.125 690 506 33.3 498 31.2 500 28.230 1020 420 32.4 394 30.5 408 25.5


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Table 3: Table of loss of load and turbidity in function of depth and time

Graph Length of column vs Pressure drop

0

200

400

600

800

1000

1200

0.00 2000.00 4000.00 6000. 00 8000.00

pressure drop

l e n g

t h o

f c o

l u m n

30 min

60 min

90 min

Graph Turbidity versus Length of Column

0

10

20

30

40

50

60

0 200 400 600 800 1000 1200

Length of Column

T u r b

i d i t y 30 min

60 min

90 min


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CALCULATIONS

Data:

Internal diameter of the column, D: 100 mm

Density of sand, p = 2650 kg / m 3

Sphericity of sand, = 0.8

Diameter of sand, d p = 1 mm

Density of water, f = 1000 kg / m 3

Viscosity of water, f = 0.001 kg / ms

Length, L = 1030 mm

Mass of bulk, m = 8.7 kg

Voidage of bed = 0.4

Voidage of the bed, bed = 1 ( b / p)

0.4 = 1 __ b kg / m 3

2650 kg / m 3

b = 1590 kg/m 3

From the figure 3 , the value of F Re = 50

From the figure 5 , the value of F f = 2500


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Sample of Calculation

Consider the first reading in experiment 1

Q = A . v a

va = Q / A

= 10 L 1 hr 1E-3 m 3 1_______

hr 3600 s 1 L 7.854 x 10 -3 m 2

= 3.537 x 10 -4 m / s

Re = (v ad p / ) F Re

= 1000 kg m -3 x 3.537 x 10 -4 m s -1 x 1E-3 m x 50

0.001 kg m -1 s-1

= 17.684

From figure 4 , for first reading = 4.0

From figure 5 , F f = 2500

H f = (L / d p) (v a2 / 2g) (F f )

= 9 x 1030E-3 m (3.537 x 10 -4 m s -1)2 (2500)

1E-3 (2) (9.81 m s -2)

= 0.0657 m

P = gh f

=1000 kg/m 3 x 9.81 m s -2 x 0.67 m


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DISSCUSSIONS

The separation of solids from a suspension in a liquid by means of a porous

medium or screen which retains the solid and allows the liquid to pass is termed

filtration. In general, the pores of the medium will be larger than the particles which

are to be removed, and the filter will work efficiently only after an initial deposit has

been trapped in the medium. The most important factors on which the rate of filtration

depends be are the pressure drop from the feed to the far side of the filter medium, the

area of the filtering surface, the viscosity of the filtrate, the resistance of the filter

cake, and the resistance of the filter medium and initial layers of cake.

For first experiment the graph that been plot from the experiment result and

theoretical result shows the similarity in the graph pattern. Its show that the particular

theory is suite for that particular experiment condition. For second experiment the

pressure drop is decreasing when the column height increase. However the pressure

drop value is similar for different time taken 30 minute, 60 minute and 90 minute.

This condition happen because the changes in concentration of solid suspend in liquid

is not affecting the pressure drop.

The value of turbidity that determine from the turbid meter is non consistent.

This is because the sand particle that used in the filter bed is not equal. However the

turbidity value is still decreasing at the maximum height of the column.


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CONCLUSIONS

1. The bed voidage is 0.4 and the bulk density is 1590 kg/m 3

2. The theoretical head loss h f of the porous bed is

Flow Rate, Q (L / hr) Hf (m)10 0.065720 0.111630 0.177340 0.210150 0.287360 0.354670 0.4022

80 0.420390 0.5319

100 0.5582

3. The data that gained from the experiment is similar to the data that obtained

from theoretical calculation using the formulation. Its show that the

experimental value is valid.

4. The nature of the flow is analyzed based on the Reynolds number

Q (m 3 / s) Re' Nature of flow

2.778E-06 17.684 laminar

5.556E-06 35.368 laminar

8.333E-06 53.052 laminar

1.111E-05 70.735 laminar

1.389E-05 88.419 laminar

1.667E-05 106.103 laminar

1.944E-05 123.787 laminar

2.222E-05 141.471laminar

2.500E-05 159.155 laminar

2.778E-05 176.838 laminar

RECOMMENDATIONS


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1. Mix the liquid with colored dye in order to differentiate the liquid in the

manometer tube with the wall scale. This is important in order to get the

accurate reading

2. All bubble must be vanish from the manometer tube by increasing water level

in manometer to the maximum value.

3. Take the average reading because the water level in the manometer tube is not

stable in order to prevent from parallax error.

REFERENCES


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Rhodes, M; Introduction to Particle Technology ; John Wiley

Coulson J. M and Richardson J. F; Chemical Engineering Volume 2 ;Butterworth Heinemann

McCabe, Smith, Harriott; Unit Operation of Chemical Engineering ; McGraw

Hill

APPENDICES


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Hazim-Lab 2